I finished a short but interesting test today. My aim was to test the effects of high bitrate lossy transcoding using conventional codecs like lame mp3 and also to test the hybrid codecs such as wavpack.

Task is simple: transcode a large lossy file into a 128k mp3 so it will be suitable for portable players. I chose lame 3.96.1 APS, wavpack lossy around 400k and freeformat mp3 at 384k. I chose freeformat to test its reliability considering the popularity of allofmp3.com. These files were transcoded into 128k mp3 cbr using lame 3.96.1 - reference is 128k mp3. 128k is still popular with the masses and makes it easier to perform tests like these. The sample I chose was the wicked 'amnesia' .

Conclusion: Amnesia is a tough sample. transcoding from APS introduces hf ringing distortions. Freeformat was a big disappointment as there was less ringing but much worse noise than APS !.

Transcoding from high bitrate mp3 to 128k is questionable and with this sample its bad news.

Wavpack showed no audiable loss to me here. I am going to do more tests soon, but for now I can say that hybrid lossy around 400k or maybe lower can be used for general archiving and transcoding when space is short or you just don't like 870k lossless files. I am not advocating it as a replacement for true lossless though but with the correction files you might get the best of both.

I chose freeformat to test its reliability considering the popularity of allofmp3.com.

Good work here. By the way, I've seen freeformat 384 kbps mentioned before in regards to allofmp3, including in a popular review out there. I signed up just for the heck of it to see what all the fuss was about (after it was mentioned on The Screensavers), and noticed that when you order sutff using their Online Encoding feature, it will tell you the source format of the file you're about to encode. 99% of the time it says -alt-preset standart (the t is a typo obviously). If true that would mean very little of their music is actually in 384 kbps freeformat. Bad news for transcoding. Makes me wonder how much of their lossless stuff can be trusted as well. The problem is you just don't know where the source came from. Plus you have no control over the ripping process (are all their songs listend to for errors?). In the end I decided I didn't really care for the service, despite it being so cheap (and yes, I know allofmp3 is a grey area legally speaking). I'd much rather be able to buy songs from a reputable store in a lossless format. Anyways, thanks for the tests. Interesting stuff.

While it was carried out quite differently from some tests I posted a year ago or so, the findings were similar. In my case, I was looking for a source lossy format for transcoding into ATRAC for Minidisc. Wavpack was much better than any of the other lossy formats at the time for this. (I have since tested Optifrog Dualstream which also works trasncodes well.)

I encoded the track 'take my breath away' by Berlin to LAME 3.96.1 V7 from FLAC and from MPC --insane. I focused on a 3 second drum intro. They seemed very close but hit a,b,y a few times and there is something wrong with the cymbals. They sounded smeared and lost sharpness.